SARCOIDOSIS DIAGNOSTIC TESTING LLC is a medical diagnostics company developing a diagnostic blood test for sarcoidosis. Sarcoidosis is a multisystem granulomatous disorder that affects ~10-40 per 100,000 people per year in the U.S. and disproportionately affects African-Americans and women. Sarcoidosis can lead to advanced pulmonary fibrosis, pulmonary hypertension, heart failure, sudden cardiac death and devastating neurologic disease. Thus, sarcoidosis represents a significant health problem and health disparity concern. Because sarcoidosis can affect any or multiple organs, sarcoidosis must be differentiated from many other inflammatory, infectious or immunologic diseases and cancer. A consensus in the medical community is that there is no useful blood test or other easy way to diagnose sarcoidosis; a diagnosis requires biopsy confirmation, often by lung or lymph node biopsy, with its attendant risks and costs. The costs involved with diagnosing sarcoidosis have not been published, but estimates could exceed $225 million each year. The need for a safer, cost-effective diagnostic blood test for sarcoidosis is clear. This Phase I application proposes to continue the development of a promising diagnostic blood test for sarcoidosis initially developed with funding from a Centers for Advanced Diagnostics and Experimental Therapeutics in Lung Diseases Stage I (CADET I) award to Johns Hopkins University. This diagnostic blood test is based on the discovery of a specific microbial protein, mycobacterial catalase-peroxidase (mKatG) that stimulates the immune system in most patients with sarcoidosis. This test uses mKatG and other microbial proteins to stimulate release of the inflammatory chemical interferon-? from blood cells to predict sarcoidosis. To date, our proposed blood test has a sensitivity of 65%, a specificity of 96% and a positive predictive value of 94%. With these promising results, we propose to further develop this test by optimizing test characteristics for different subgroups with sarcoidosis and to establish the reliability and operating range of laboratory procedures for this test. In this Phase I proposal, we will also develop a commercial prototype diagnostic kit to test the feasibility of deploying the test in different geographic centers. Finally, we will establish a marketing approval process with the FDA and complete a framework for a prospective multicenter study to validate this test as part of a Phase II application. If successfully validated in Phase II studies, the test could have a transformative impact on how clinicians diagnose sarcoidosis given the absence of an alternative safe and cost-effective test. Such a test would have a high potential for commercial application and with widespread use could result in considerable cost savings to the U.S. healthcare system.